package com.itbour.common.util;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

	public class DESUtil {  
		   
	    Key key ;  
	   
	    public DESUtil() {  
	   
	    }  
	   
	    public DESUtil(String str) {  
	       setKey(str); // 生成密匙  
	    }  
	   
	    public Key getKey() {  
	       return key ;  
	    }  
	   
	    public void setKey(Key key) {  
	       this . key = key;  
	    }  
	   
	    /** 
	      * 根据参数生成 KEY 
	      */  
	    public void setKey(String strKey) {  
	       try {  
//	           KeyGenerator _generator = KeyGenerator.getInstance ( "DES" );  
//	           _generator.init( new SecureRandom(strKey.getBytes()));  
	           this.key = this.generateKey(strKey);  
//	           _generator = null ;  
	       } catch (Exception e) {  
	           throw new RuntimeException(  
	                  "Error initializing SqlMap class. Cause: " + e);  
	       }  
	    }  
	    /**
		 * 获得秘密密钥
		 * 
		 * @param secretKey
		 * @return
		 * @throws NoSuchAlgorithmException 
		 */
		private SecretKey generateKey(String secretKey) throws NoSuchAlgorithmException{
			//防止linux下 随机生成key
			SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
			secureRandom.setSeed(secretKey.getBytes());
			
			// 为我们选择的DES算法生成一个KeyGenerator对象
			KeyGenerator kg = null;
			try {
				kg = KeyGenerator.getInstance("DES");
			} catch (NoSuchAlgorithmException e) {
			}
			kg.init(secureRandom);
			//kg.init(56, secureRandom);
			
			// 生成密钥
			return kg.generateKey();
		}
	    /** 
	      * 加密 String 明文输入 ,String 密文输出 
	      */  
	    public String encryptStr(String strMing) {  
	       byte [] byteMi = null ;  
	       byte [] byteMing = null ;  
	       String strMi = "" ;  
	       BASE64Encoder base64en = new BASE64Encoder();  
	       try {  
	           byteMing = strMing.getBytes( "UTF8" );  
	           byteMi = this .encryptByte(byteMing);  
	           strMi = base64en.encode(byteMi);  
	       } catch (Exception e) {  
	           throw new RuntimeException(  
	                  "Error initializing SqlMap class. Cause: " + e);  
	       } finally {  
	           base64en = null ;  
	           byteMing = null ;  
	           byteMi = null ;  
	       }  
	       return strMi;  
	    }  
	   
	    /** 
	      * 解密 以 String 密文输入 ,String 明文输出 
	      * 
	      * @param strMi 
	      * @return 
	      */  
	    public String decryptStr(String strMi) {  
	       BASE64Decoder base64De = new BASE64Decoder();  
	       byte [] byteMing = null ;  
	       byte [] byteMi = null ;  
	       String strMing = "" ;  
	       try {  
	           byteMi = base64De.decodeBuffer(strMi);  
	           byteMing = this .decryptByte(byteMi);  
	           strMing = new String(byteMing, "UTF8" );  
	       } catch (Exception e) {  
	           throw new RuntimeException(  
	                  "Error initializing SqlMap class. Cause: " + e);  
	       } finally {  
	           base64De = null ;  
	           byteMing = null ;  
	           byteMi = null ;  
	       }  
	       return strMing;  
	    }  
	   
	    /** 
	      * 加密以 byte[] 明文输入 ,byte[] 密文输出 
	      * 
	      * @param byteS 
	      * @return 
	      */  
	    private byte [] encryptByte( byte [] byteS) {  
	       byte [] byteFina = null ;  
	       Cipher cipher;  
	       try {  
	           cipher = Cipher.getInstance ( "DES" );  
	           cipher.init(Cipher. ENCRYPT_MODE , key );  
	           byteFina = cipher.doFinal(byteS);  
	       } catch (Exception e) {  
	           throw new RuntimeException(  
	                  "Error initializing SqlMap class. Cause: " + e);  
	       } finally {  
	           cipher = null ;  
	       }  
	       return byteFina;  
	    }  
	   
	    /** 
	      * 解密以 byte[] 密文输入 , 以 byte[] 明文输出 
	      * 
	      * @param byteD 
	      * @return 
	      */  
	    private byte [] decryptByte( byte [] byteD) {  
	       Cipher cipher;  
	       byte [] byteFina = null ;  
	       try {  
	           cipher = Cipher.getInstance ( "DES" );  
	           cipher.init(Cipher. DECRYPT_MODE , key );  
	           byteFina = cipher.doFinal(byteD);  
	       } catch (Exception e) {  
	           throw new RuntimeException(  
	                  "Error initializing SqlMap class. Cause: " + e);  
	       } finally {  
	           cipher = null ;  
	       }  
	       return byteFina;  
	    }  
	   
	    /** 
	      * 文件 file 进行加密并保存目标文件 destFile 中 
	      * 
	      * @param file 
	      *             要加密的文件 如 c:/test/srcFile.txt 
	      * @param destFile 
	      *             加密后存放的文件名 如 c:/ 加密后文件 .txt 
	      */  
	    public void encryptFile(String file, String destFile) throws Exception {  
	       Cipher cipher = Cipher.getInstance ( "DES" );  
	       // cipher.init(Cipher.ENCRYPT_MODE, getKey());  
	       cipher.init(Cipher. ENCRYPT_MODE , this . key );  
	       InputStream is = new FileInputStream(file);  
	       OutputStream out = new FileOutputStream(destFile);  
	       CipherInputStream cis = new CipherInputStream(is, cipher);  
	       byte [] buffer = new byte [1024];  
	       int r;  
	       while ((r = cis.read(buffer)) > 0) {  
	           out.write(buffer, 0, r);  
	       }  
	       cis.close();  
	       is.close();  
	       out.close();  
	    }  
	   
	    /** 
	      * 文件采用 DES 算法解密文件 
	      * 
	      * @param file 
	      *             已加密的文件 如 c:/ 加密后文件 .txt * 
	      * @param destFile 
	      *             解密后存放的文件名 如 c:/ test/ 解密后文件 .txt 
	      */  
	    public void decryptFile(String file, String dest) throws Exception {  
	       Cipher cipher = Cipher.getInstance ( "DES" );  
	       cipher.init(Cipher. DECRYPT_MODE , this . key );  
	       InputStream is = new FileInputStream(file);  
	       OutputStream out = new FileOutputStream(dest);  
	       CipherOutputStream cos = new CipherOutputStream(out, cipher);  
	       byte [] buffer = new byte [1024];  
	       int r;  
	       while ((r = is.read(buffer)) >= 0) {  
	           cos.write(buffer, 0, r);  
	       }  
	       cos.close();  
	       out.close();  
	       is.close();  
	    }  
	   
	    
	  public static void main(String[] args) throws Exception {  
	       DESUtil des = new DESUtil( "1234567" );  
	       // DES 加密文件  
	       // des.encryptFile("G:/test.doc", "G:/ 加密 test.doc");  
	       // DES 解密文件  
	       // des.decryptFile("G:/ 加密 test.doc", "G:/ 解密 test.doc");  
	       String str1 = " 要加密的字符串 test" ;  
	       // DES 加密字符串  
	       String str2 = des.encryptStr(str1);  
	       // DES 解密字符串  
	       String deStr = des.decryptStr(str2);  
	       System. out .println( " 加密前： " + str1);  
	       System. out .println( " 加密后： " + str2);  
	       System. out .println( " 解密后： " + deStr);  
	    }
}
